S-Corporation Tax Rules: Election, Reasonable Salary & 1120-S Filing

The S corporation is the most common tax-savings election for profitable owner-operated businesses because it splits a single stream of profit into two differently taxed buckets. Salary is exposed to the 15.3 percent FICA wedge; distributions are not. But the strategy is governed by hard eligibility limits and the IRS’s reasonable-compensation doctrine, and getting either wrong converts a planning win into an audit exposure.

Eligibility and the Form 2553 Election

S-corporation status is not a business structure but a tax election available to eligible domestic corporations and LLCs. The statutory limits under IRC §1361 are precise: no more than 100 shareholders, only one class of stock, and shareholders restricted to US citizens or resident individuals, certain trusts, and estates. Nonresident aliens, partnerships, and most corporations cannot be shareholders.

The election is made on Form 2553, signed by all shareholders, and is generally due within two months and fifteen days of the start of the tax year in which it takes effect. An LLC that wants S treatment files Form 2553 as well (and is deemed to make the underlying corporate election), which is why “LLC taxed as an S-corp” is so common.

Salary vs Distribution: Tax Treatment Matrix

The S-corp strategy works because the two profit components are taxed differently, as the matrix shows.

The Reasonable Compensation Doctrine

The S-corp advantage hinges on paying yourself a defensible salary. The IRS requires shareholder-employees who provide services to receive reasonable compensation — a market-rate W-2 wage — before taking distributions. That wage is subject to Social Security and Medicare withholding and is reported through quarterly Form 941 filings and an annual W-2.

There is no statutory formula; reasonableness is a facts-and-circumstances test weighing training and experience, duties and time devoted, comparable salaries for similar roles, and what the business could pay an outsider to do the work. Setting an artificially low salary to maximize distributions is a primary audit trigger, and the IRS can recharacterize distributions as wages and assess back FICA, penalties, and interest.

Pass-Through Mechanics and Form 1120-S

The S corporation files Form 1120-S and issues each shareholder a Schedule K-1 reporting their pro-rata share of income and deductions. Shareholders pay income tax on that share whether or not it is distributed, and distributions themselves are generally tax-free to the extent of stock basis. Crucially, neither the K-1 distributive share nor cash distributions carry self-employment tax — only the W-2 salary does.

Two anti-abuse provisions can still impose entity-level tax: the built-in gains tax under §1374 on appreciated assets carried over from a former C corporation, and the tax on excess net passive income. Most owner-operated service businesses encounter neither, but former C corporations converting to S status must model both.

When the S-Corp Election Actually Saves Money

The election only pays once profit comfortably exceeds a reasonable salary, because the savings come from the spread between total profit and the wage you must still pay. As a rough planning guide, net profit in the $40,000 to $80,000 range is where the FICA savings begin to outweigh the added cost of running payroll, filing Form 1120-S, and maintaining corporate formalities.

Consider an owner with $120,000 of net profit who pays a $70,000 reasonable salary. FICA applies to the $70,000 wage, but the remaining $50,000 taken as distributions avoids the 15.3 percent self-employment wedge, saving roughly $7,000 to $7,500 annually — net of payroll and compliance overhead. Below the break-even, the administrative cost erases the benefit.